


I Need A Favour

by centerpiece_centipede



Category: Shingeki no Kyojin | Attack on Titan
Genre: Canon Universe, Cunnilingus, Established Relationship is Yumikuri, F/F, F/M, Lesbians, Oral Sex, Rimming, STDs, STIs, Smut
Language: English
Status: In-Progress
Published: 2014-12-27
Updated: 2015-07-11
Packaged: 2018-03-03 18:40:07
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 6
Words: 4,796
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2862617
Author URL: https://archiveofourown.org/users/centerpiece_centipede/pseuds/centerpiece_centipede
Summary: <blockquote class="userstuff">
              <p>Ymir has a cold sore on her mouth and can't satisfy her girlfriend, Christa. She asks Bertholdt for a favour...</p><p>[Takes place some time during 104th sqn's training, before graduation].</p>
            </blockquote>





	1. Ymir needs a favour

**Author's Note:**

> Yes, I'm a guy. Yes, I write fanfiction. First SNK fanfic ever, first smutty fanfic ever. Plz leave comments.  
> Smut will be later on in story, want to set up context first.

Bertholdt had to excuse himself from the crowded dining hall to get some air. The teen wasn’t used to being somewhere with so many people, except for a few years ago when Wall Maria was breached and everyone was pushing and shoving to escape from the titans.

He shook that memory from his head and tried to block it. The night air was much cooler than inside and he felt himself relax slightly, he could feel the tension disappear from his shoulders and he had room to move freely. 

There was a quiet creak from behind him and his defensive instincts kicked in. Bertholdt spun his body around to see a vaguely familiar face, Ymir. He’d never spoke to her but he’d noticed the tallish, dark skinned girl when was usually with short, blonde Christa, who Reiner often tried to speak to.

He relaxed again, assuming she would just walk somewhere else but he was surprised when she made her way over to where Bertholdt was leant against the balcony. Ymir wore her ever-present frown as she did so but it upturned into a slight smile when she saw him begin to sweat nervously.

“Um…” Bertholdt wasn’t sure what she wanted and was anxious about what she was going to say to him.

“Hey” she said casually but the smile on her face made him think that she didn’t just come out there to greet him.

He noticed a small mark on the side of her mouth that wasn’t there before.

“Hi...err, did you need something?” he wasn’t used to socialising and the girl’s intimidating nature made him even more nervous.

“Hmm” Ymir let out a slight laugh; she seemed very out of character “I came to ask of a favour from you”.

Berthold remained silent and tilted his head to the left slightly to prompt her to continue. He vaguely wondered whether this was anything to do with his secret but figured that she probably wouldn’t be acting as calm around him if she’d figured it out.

She stepped to the side of him and leant on the balcony next to him, as if giving him an escape route if he felt too uncomfortable. Of course, Bertholdt was too polite to just run away. He cast his eyes towards the entrance back into the dining hall and wondered whether Reiner or somebody would come to rescue him from this awkward situation.

“Are you a virgin, Bertholdt?” Ymir asked bluntly, still staring at the wall in front of her. He stared blankly at the shorter girl, wondering whether he’d misheard.

“Hmm?” she prompted again “Well, are you?”.

He pushed himself away from the barrier and stepped away from her slightly. Bertholdt felt his heart rate speed up as he didn’t know how to answer the question. He understood what she was asking, he’d heard the other boys discussing it often in the barracks and he’d attempted to block out those kinds of conversations.

“I...I …err, umm” Bertholdt stuttered, as if he’d suddenly lost his ability to string words together and form a sentence.

“Have you ever had sex?” she said each word clearly, as if she were talking to a small child (well, the question probably wouldn’t be aimed at a small child but she spoke as if he couldn’t understand English very well). He could tell Ymir was getting impatient with him.

Bertholdt thought to question her asking him this but saw her crossed arms and her face growing more annoyed after every second that he remained silent. Now she was being more in character.

“No” he answered simply; Bertholdt was a complete and utter virgin.

Her face was unjudging and seemed to say “fair enough”, it’s not like they had much free time on their hands while training to fight titans, especially not to sneak away and do something like that. Also, Bertholdt wasn’t exactly the best at charming people.

“So I’m guessing you’ve never given oral to a girl then?” again, she didn’t seem embarrassed at all about this topic whilst Bertholdt was almost trying to melt himself into the floorboards at this point.

He wished she would be more subtle or at least try to keep her voice down, if anyone heard them he would run and find the nearest titan and literally jump into its mouth.

Unable to speak, he shook his head. Ymir chewed the inside of her cheek as she pondered something.

She glanced at the clock, which was just above the door, and saw that they only had a few minutes left of dinner. She took a pencil and a bit of paper out of her pocket then began to write something down. Bertholdt waited awkwardly for her to finish.

She smiled and handed him the paper, which she’d folded up.

“Open it later, make sure nobody else reads it” she told him “I can tell you’re uncomfortable and we don’t have much time left so I’ll leave it at that. See you soon, maybe”.

Bertholdt watched her walk down the dining hall steps then in the direction of the girls’ barracks. He looked down at the note she’d given him and contemplated opening it at that second but decided to shove it in his pocket. He’d been patient for these few years during his time at the training camp; surely he could wait a few more minutes to quench his curiosity.


	2. The Note

**Summary for the Chapter:**

> Bertholdt reads Ymir's mysterious note, he'd surprised by what he reads. He isn't sure whether to help or not...

**Notes for the Chapter:**

> Second chapter, written at 2am.

The tall teenager retreated back into the dining hall and headed straight for his best friend, Reiner. The blonde was still deep in conversation with Jean, talking about which girls they have crushes on.

Bertholdt vaguely heard Reiner mention something about Christa. Jean, of couse, said something about a certain somebody's 'beautiful, black hair'.

When Bertholdt sat down next to Reiner he tapped his friend on the shoulder to make sure he didn’t go unnoticed, he hated being invisible. 

“Oh, Bertl, hey! Where’d you go?” Reiner questioned as he turned to face him in surprise.

“Just needed some fresh air” Bertholdt shrugged. It wasn’t a total lie, that was his original intention when he’d left to go outside before he encountered Ymir, he’d just left that part out. He was good at keeping secrets by now.

“Oh ok, you feeling alright now?” Reiner seemed concerned about his friend, knowing how nervous he could get, and placed a hand on Bertholdt’s shoulder.

“Yeah, yeah, I’m fine” Bertholdt reassured him with a small smile. 

He slipped a hand into his pocket to scrunch the folded paper that was still a mystery to him, just to make sure it was still there. He rubbed the crease where Ymir had haphazardly folded the note unevenly in a hurriedly. He held the paper as if he could absorb the information that it held and read it without opening it.

As he replayed the events that occurred outside, the bell went off the signal the end of dinner and the hall began to empty. Bertholdt took his tray up to the racks then filtered out of the door, along with all of the other cadets and headed to the boys’ barracks.

He and Reiner made their way over to their shared bunk and began to get dressed into their night clothes. Normally Bertholdt was glued to Reiner’s side all the time but now he was almost desperate for his friend to leave him alone for just a moment so he could read this mysterious note.

As if he’d heard Bertholdt’s internal begging, Reiner excused himself to go to the toilet outside. Bertholdt took this as his chance to read the note while he the candles were still lit and he had a moment of privacy.

It was fairly brief as Ymir had only spent a few seconds writing it but she definitely got her point across.

[[[  
‘I need a favour. Remember the  
last question I asked you? If you’d  
like to help out, come to the storage shed  
at 3am when the guard shifts change.  
–Ymir’  
]]]

He thought back to their talk again, remembering it vividly from replaying it over and over in his head. What was the last question she’d asked him?

“So I’m guessing you’ve never given oral to a girl then?”

A deep blush formed on his face as he recalled what she’d asked him. He wondered whether he’d misinterpreted this or not.

Could this really be what she was asking him? Suddenly, a familiar voice startled him out of his thoughts. 

“Hey”, Reiner announced his return, the greeting was deafening as Bertholdt returned from his mind.

Of course, even if Reiner did read it, he wouldn’t know what she was talking about. Bertholdt silently thanked the usually very blunt woman for being vague this time.

“N…nothing” Bertholdt obviously lied, scrunching the offending object into a tiny ball in his hands, hoping that if he squeezed it tight enough, it would disappear and Reiner would forget all about it.

The muscular blonde raised an eyebrow at his friend’s sudden strange behaviour, curious about the note, but he decided it probably wasn’t that important and even Bertholdt was allowed to keep secrets. Maybe he was just too tired but he decided to respect Bertholdt’s privacy.

“Kay, whatever” Reiner shrugged, yawned then climbed into his respective side of the bed.

Bertholdt looked at him in surprise, expecting him to play some sort of trick and steal the note out of his hands. Cautiously, he put the note back into his pocket and crawled over to his own side of the bed, grateful that Reiner trusted him to be responsible for his own secrets.

As he lay under his warm covers, Bertholdt asked himself whether he was actually going to grant Ymir this favour. 

He had no sexual experience. She wanted him to give her oral? Until now, Bertholdt had thought she was strictly into women and he thought she was with Christa?

After a mental battle, he thought it would do him no harm just to see whether he wanted to or not. After all, this may be his last chance for any sexual encounter.

He calculated how many hours he would need to sleep for in order to wake up on time to meet Ymir. Back in his home town, they were trained on special breathing techniques for different lengths of sleep. 

Bertholdt closed his eyes as he took a long, deep breath followed by several short breaths then another long one.

**Notes for the Chapter:**

> Next chapter- Bertholdt goes to the storage shed


	3. Storage Shed

**Summary for the Chapter:**

> Bertholdt sneaks out to the storage shed to find that the situation is slightly different than planned...

**Notes for the Chapter:**

> Almost there

Bertholdt woke up just in time to faintly hear three echoing chimes from the clock tower. The noise wasn’t loud enough to wake any of the other cadets luckily, just to alert the guards to change shifts.

The tall teenager carefully climbed his way over Reiner and slipped his shoes and coat on on. Luckily for him, his blonde friend was a rather deep sleeper.

His senses were better than almost every other cadet in the training camp so he could easily hide if somebody were to find him.

Bertholdt snuck his way over to the door and opened it just enough for him to see through a tiny crack, he saw the previous guard walking away to the staff barracks and knew that he had to act fast before another one arrived any moment later.

He hid in the shadows and quietly made his way over to the designated meeting spot, the storage shed.

On his way there, Bertholdt considered that this whole set up might be a trap. He wondered if Ymir had somehow figured out his secret…

He shook his head of these nervous thoughts and decided that he was just being paranoid. How would she have found out anyway? He was just being silly.

Anyway, if that were the case he would easily be able to overpower her considering he’d used his special sleep technique that maximised his sleep cycles so he’d be more alert than her and able to fight back. Not to mention his other advantage against her as a last resort if it came to that…

The small building came into his view after a few minutes of sneaking around and avoiding the guards. This particular area of the training ground wasn’t very heavily guarded so it was a convenient place for the planned situation to occur in.

After cautiously scanning the area to make sure he wouldn’t get caught, and also to ensure he wasn’t walking straight into a trap, he approached the building to find that the door was already unlocked. 

Bertholdt opened the door just enough to see inside. It was pitch black and appeared empty.

He was about to give up, close the door and sneak back to his barracks when he heard somebody whisper “Bertholdt” from somewhere within the darkness.

The named boy jumped at the sudden break of silence by the tiny voice before he recognised it as his squad member, Christa. He walked towards the sound of her voice then heard the door shut behind him.

He spun around quickly, ready to apologise to a guard, when instead he saw Ymir standing with her hand to the door.

“Glad you could make it, Berty” she smirked at him before clipping a padlock on the door. She then lit a candle which immediately filled the small room with a blanket of warm, orange light. Bertholdt noticed that somebody had purposefully covered the small window with a wooden board to stop the light from escaping and alerting an onlooker from outside. 

He looked to the intimidating brunette and then back down at the short blonde girl, he also noticed that Christa had a slight blush across her face.

“Err..So…?” Bertholdt awkwardly prompted to anybody who would explain the situation. Ymir let out a small laugh at his shyness then proceeded to spare him from his confusion.

“I’ll cut to the chase, I’m guessing you figured out what you’re here for but you’re confused as to why Christa is here, am I correct?” the Swedish girl asked him.

Bertholdt nodded his confirmation, a blush also rising to his own cheeks.

“C’mere” Ymir beckoned him to lean down and she tilted her head slightly so he could see the sore on her mouth that he’d noticed earlier.

“Basically, my mouth is a special tool that I use to give my girlfriend pleasure, got it?” she spoke to him in simple terms as she had before.

“And because of this temporary skin condition” Ymir pointed to the sore, “my special tool is currently out of action…”.

Bertholdt was silent as he processed this information then it clicked why she had seemingly randomly asked him to meet her here.

“So…um, you need me use my mouth on your girlfriend because you can’t” he made sure.

“Bingo” Ymir patted him on the back, patronisingly, “You up for it? I’m guessing so since you had no problem meeting me here” she smirked again.

Bertholdt supposed it didn’t really make much of a difference since he had originally agreed to perform oral on Ymir but Christa was a friend in need, so..

“Err…sure” he confirmed.

“Brilliant!” Ymir led him and Christa over to the back of the storage shed where there a small set up of blankets on the floor.

Ymir sat down on the pile first then allowed her girlfriend to sit in her lap then lovingly wrapped her arms around her. Bertholdt almost thought that the two lesbians’ display was rather adorable as he took his coat off and knelt down in front of Christa.

The blonde girl was obviously rather anxious about this situation but Bertholdt could also tell that she was desperate. And who was he to deny his comrade a favour?...

**Notes for the Chapter:**

> Next chapter will be smut :3


	4. (X) Christa

**Summary for the Chapter:**

> The smut begins... enjoy

Bertholdt shuffled nervously a little to get into the correct position to reach between her legs. His heartbeat sped up slightly in anticipation, nevertheless he felt excited at the same time.

He’d never actually seen a female’s genitalia before, only having minimal knowledge from the other trainee’s wild tales of their experiences. They’d said that the vagina became wetter when a girl when they were enjoying what you did to them. And that the most sensitive area was a small bump on top of the hole. Bertholdt had tried to imagine what all this would look like in real life but he’d ended up even more confused and curious.

“Ready?” Ymir asked, snapping him out of his trance-like state as he stared at Christa’s covered crotch.

He nodded and Ymir lifted the dramatically skirt as if it was a stage curtain. Bertholdt was surprised by how different the female body was to a male one. Christa’s vagina was bordered with a forest of blonde pubic hair, trailing down to where the mound parted into two lips. Another section of skin peaked out from between the lips, this was a darker pink but he still couldn’t see this sensitive bump that the others had spoken about. 

Bertl just stared for a little while and calculated where to start first. This strange contraption was actually rather cute compared to the horrifying labyrinth he had imagined a vagina would be.

Christa began to get uncomfortable the longer he just looked between her legs, she felt exposed yet she made no move to cover herself.

“Well, get on with it then” Ymir commanded as she began to get impatient.

“Um, where exactly do I…?” Bertholdt trailed off.

“Damn, forgot you hadn’t done this before” Ymir sighed then began to explain the proper procedure of cunnilingus.

“It’s fairly simple” she shuffled to use both hands on Christa, using one to spread apart the lips and another to point.

“This is the clitoris” she pointed towards the bump, “it’s really sensitive and feels good when you lick it but not directly or too much because that’s just a sensation overload”.  
Bertholdt nodded, making notes in his head as if were learning in class.

“This is the vagina” she referred to the hole as she spread the lips even further “You can lick around it or put your tongue in there if you wish, maybe even a few fingers but don’t hurt my baby girl, got all that?”

Bertholdt nodded again. He was determined not to mess this up.

“Great, don’t worry, I’ll guide you if you’re being a bit sloppy just use your tongue and vary your patterns and stuff, ‘kay? Go on then”, she leant back again to allow Bertholdt access.

He leaned in and gave a tentative lick to the outside of her pussy, as if it were going to bite him. Christa jumped a little in surprise and let out a small squeak at the unfamiliar tongue but quickly moved back towards his mouth. Bertholdt looked up at her to check she was okay then returned back to his task. 

He licked again, this time with more enthusiasm, his large tongue wetting her lips. He repeated the motion as Christa let out small moans at the feeling and Ymir watched in satisfaction as he began to learn.

**Notes for the Chapter:**

> Next chapter will be longer ;)


	5. (X) Favour

**Summary for the Chapter:**

> Everyone's out of character, everything's over the top. Here's the main stuff.

He dipped his tongue between the lips and tasted an existing wetness that wasn’t his own saliva. It tasted rather sweet yet tangy and he realised that this must indicated Christa’s arousal. 

Bertholdt wrapped his arm around her leg and used his fingers to spread out her pussy and find this small bump that Ymir had referred to as ‘the clitoris’. 

He ran his tongue along it lightly and the blonde girl thrust forwards, prompting him to apply more pressure. Her tuft of light pubic hair felt soft as it brushed against his face. 

While he tasted his comrade’s clit, he realised that his nervousness had vanished and he was actually beginning to have fun.

“You’re doing great” he heard Ymir coach him from above. He looked up to see Christa suckling on her neck because the other girl couldn’t risk her girlfriend catching whatever infection she had on her mouth.

Bertholdt let out a small laugh at the sight of the cute couple which caused Christa to yelp at the vibration before continuing on her girlfriend’s neck. Ymir looked down at the boy and winked. He blushed slightly and continued his own task. 

Ymir moved her hands around Christa’s chest to cup her small breasts and squeezed them.

As he began to get braver, he ventured down to ‘the vagina’ and lapped his tongue at the hole. Christa had to pull away from Ymir to moan deeply as the delicious feeling of his invading tongue. Bertholdt surprisingly heard himself moan also as his own genitalia grew harder.

He ignored his own needs to first satisfy Christa and dipped his tongue inside of the tight, wet hole. Bertholdt felt himself completely immersed inside her and couldn’t stretch his tongue any further. Christa whimpered and wrapped herself around Ymir, too pleasured to concentrate on anything but the heavenly mouth on her pussy.

“Don’t forget that you can use your hands as well,” Ymir advised him “it tons feels better when you pleasure the clit and the vagina at the same time”.

He pulled his tongue out of Christa’s delicious hole and used his middle finger to apply pressure to rub her clitoris while he could still keep eating her out. Bertl experimented a little, rubbing in different patterns and listening out for indications in Christa’s desperate little moans and whimpers. He felt as if he was trying to tune in on a specific radio frequency. 

He figured that she reacted best when he rubbed at her in small clockwise circles so he shifted down again to reinsert his tongue. She tasted brilliant and Bertholdt wondered why he’d never bothered to try this out before, he reminded himself to thank Ymir later for this delicious opportunity. 

He bobbed his tongue in and out as if he were lost in the wilderness, dying of dehydration and was savouring the last precious drops of water from his bottle. This first experience of sex had turned him into a mindless, horny animal and gave into his craving.

Wanting to try out all the different methods, he pulled his tongue from her again after one last deep lick and brought his hand down to her entrance instead. Remembering Ymir’s warning, he inserted his index finger slowly and heard Christa moan. She was dripping wet and his finger slid in easily.

“Forgot to say, there’s also something called ‘the G-spot’ inside the vagina” Ymir interrupted once again, Bertl was actually surprised that all of this periodic lecturing hadn’t yet ruined the mood but her hints and tips just seemed to make the situation better for everyone, “just twist your fingers to face upwards, like this”. She made a ‘come here’ motion with her fingers in the air and Bert attempted to mimic her movements inside of Christa’s pussy.

“Mmn, yeah, do that again” the blonde girl urged him to continue. 

“Thrust in and out a bit too, maybe add another finger” Ymir suggested. She moved her hands from Christa’s breasts and snaked them up her shirt to touch them directly. Ymir quickly found her nipples and rubbed them between her fingers.

As Bertholdt kept thrusting his fingers inside of Christa, always aiming at this spot, he watched how Ymir was teasing her girlfriend’s nipple and he thrusted his hips against the floor as a natural reflex.

He returned his mouth to lick and suck on the blonde girl’s clit again as Ymir had instructed him. The small bump twitched as he wrapped his whole mouth around it, still thrusting his fingers inside of Christa’s pussy.

“I’m… mmn …so close” Christa struggled to inform them. She panted and pushed back against Bertl’s fingers, leaning on her girlfriend for support.

Bertholdt was slightly confused as to what she meant, having never had sex before. 

“It means she’s going to orgasm soon, dummy, speed up a bit” Ymir explained, rolling her eyes, then she began to reassure Christa “C’mon baby girl, we’ve got you. Cum for me”. 

Bertl thrust harder and faster into Christa’s hole, applying more pressure on her clit with his tongue. 

All of a sudden, Christa seemed to go into a weird frenzy and her clit twitched more and her pussy tightened around Bertholdt’s fingers.

Her body shook in pleasure as she orgasmed.

“Shh, shhh, it’s okay, babe. There we go, there we go” Ymir spoke to her as if she were a small pet.

Christa eventually began to relax and Ymir shooed Bertholdt away from her girlfriend’s sensitive pussy. He had felt her get wetter as she came and wanted to taste more of the fluid. Sneakily, he took another lap between her sensitive wet folds, avoiding her clit, as he cleaned the delicious fluid off her. Christa didn’t seem to mind too much and tiredly opened her legs wider for him to clean her.

Ymir held the exhausted girl against her chest as she cautiously watched Bertholdt still eagerly licking at Christa’s pussy. 

“Okay, okay, that’s enough for tonight” she pulled Bertl away from Christa by his hair and re-covered Christa’s crotch with her skirt.

“Hmm, well that went well” Ymir said casually as if she were just talking about the weather.

Bertholdt hummed his agreement while sucking his fingers that had been inside Christa.

“We should do this again sometime”, the tired blonde girl mumbled against Ymir’s breast.

Bertl was actually excited about the idea of repeating this encounter or even anything else the two girls were willing to offer him. Of course, he respected that the couple loved eachother very much and his aim wasn’t to split them apart, he was merely curious and horny. Suddenly, he remembered that he was still turned on as hell and his erect penis that hadn’t yet had a release.


	6. (X) Thank You

**Summary for the Chapter:**

> Ymir tries to return the favour

Unashamed, he slid a hand into his trousers and wrapped it around his erection. Ymir quickly noticed him masturbating considering that he wasn’t even bothering to be subtle about it and she thought that she may as well help since he’d already done her a favour.

She laid Christa down on the floor gently to let her rest. She rolled her eyes at Bertholdt and walked over to him, keeping her poker face on. He noticed the shadow suddenly loom over him and stopped his hand movements. 

Ymir bent down and they locked eyes. Bertholdt seemed to get slightly embarrassed as she cast her eyes downwards towards his crotch. She shooed his hand away and briefly contemplated doing the job for him but decided against it. 

She silently pushed at his chest and he got the message to lie down. Ymir pulled his trousers down even more then spread his legs. Bertholdt watched her cautiously and stayed still, letting her lead him like a puppet, while trying to figure out her intentions. She mimicked the position that Bertholdt had earlier taken between her girlfriend’s legs. A blush crept up onto the tall boy’s face through his confusion.

Being far less awkward and hesitant than Bertholdt, Ymir just got right to the job at hand and swiped her tongue across his hole. He jumped slightly and yelped in surprise but didn’t move away, still curious. He and Ymir locked eyes as she took in his reaction then repeated the action, this time she was slower and allowed her tongue to linger there for longer.

Bertholdt decided that although it felt weird, the sensation definitely wasn’t unpleasant. Christa sat up to observe the pair through her tired eyes. 

“What’s the matter?” Ymir asked casually, with a teasing smile on her face. Bertholdt’s embarrassment had come back now that he couldn’t bury his face in Christa’s crotch and lose himself in there. He supposed it was kind of like what he did to Christa except he wasn’t a biological female so Ymir had to kind of adapt it, he was sure that the girl wasn’t too fond of male genitalia anyway.

“Hang on, I thought you couldn’t use your mouth because of that sore!” he suddenly realised and pointed out to her. Through all the excitement he almost forgot why she’d needed his ‘help’ in the first place.

“Well, yeah, I didn’t wanna risk Christa catching anything” Ymir said as if it was obvious.

“But… but you’d risk me catching… no, no, no” he shifted his butt away from her diseased face and started to pull up his underwear.

“Wait a sec” she held his hands to his thighs and stopped him from retreating “Chill, I only used my tongue a bit, not my whole mouth, you’ll be fine. But, if you’d prefer, I can use… other methods”.

“I’ll do it!” Christa suddenly blurted out from where she was watching the pair, raising her hand in the air to volunteer as if she were in a classroom.

**Author's Note:**

> Next chapter- we find out what the note says...


End file.
